Women more prone to knee injuries

Laura Geggel
Dan Daranciang

Less than one month into her freshman year two years ago, Cristina Fernandez tore her anterior cruciate ligament while practicing for club soccer.

“I was just going in for a tackle. My foot didn’t hit the ball, it didn’t hit anybody, I just sort of kicked it out in kind of an awkward position,” Fernandez said. “As soon as I did, I just felt something inside of me completely rip apart. I heard it, I felt it, and as soon as I fell to the ground, I knew it was an ACL tear. It was the worst pain I had ever felt in my entire life.”

“You always read that women are more prone to these injuries, but you never actually think that it’s going to happen to you,” she said.

Anterior cruciate ligament (ACL) tears, patella femoral pain and iliotibial (IT) band syndrome are just a few injuries that women tend to experience more than men, according to new research from the Washington University School of Medicine.

“It all stems back to the differences in anatomy: how the pelvis is formed and how the connection to the lower limb occurs [in women],” explained Devyani Hunt, M.D., instructor of physical medicine and rehabilitation in orthopedic surgery at the School of Medicine, who just co-authored a study with Heidi Prather, D.O., assistant professor of physical medicine and rehabilitation in the same department. Their study, “Issues Unique to Female Runners,” was published in Physical Medicine and Rehabilitation in Clinics of North America.

“Because of the width of the hip and the angles of the knee and the hip, there are different forces that go across the knee that make them more prone to patella femoral syndrome and the non-contact ACL tears,” said Hunt.

The ACL, one of four ligaments involved in stabilizing the knee, connects the femur of the upper leg to the tibia below the knee. By preventing the tibia from coming too far forward, the ACL deters dislocation of the knee joint.

Ligaments, which connect bones or cartilages at a joint, are made of tough, fibrous rope-like material. True to its name, the anterior cruciate ligament crosses with the posterior cruciate ligament to form an X, or a cruciate (cross), at the knee.

Richard Larsen, Washington University’s head athletic trainer, has catalogued the occurrence of 33 ACL injuries over the past 12 years. While football leads the list with 16 total ACL injuries, probably because of the greater forces football players undergo, women’s soccer and basketball each had six tears, three times as many when compared to both men’s soccer and basketball, which each had two ACL injuries.

“It was striking that we have exactly the same difference – like a third – of the amount of injury in both men’s sports as we have in women’s,” said Larsen.

University statistics reflect a greater national average. In 1999, Timothy Hewett, Ph.D., from the Cincinnati Sports Medicine Research and Education Foundation, tracked 1,263 high school athletes and collected data on their knee injuries. He found that among untrained athletes, who tended to injure themselves more, women were about five to six times more likely than their male counterparts to sustain a knee injury. Trained female athletes were 1.3 to 2.4 times more likely than male athletes to hurt their knees.

While Larsen agreed that women experience more ACL tears because of their differences in anatomy, he also pointed to muscle conditioning as a large factor.

“A lot of it is preexisting body structure. Then from there it’s how much conditioning the person’s been able to do to prepare themselves for the sport,” he said.

Hunt agreed and offered some additional ideas, noting that hormones, in particular estrogen and progesterone, affect laxity, or how much a muscle or ligament can stretch, which in turn affects muscle bulk.

“If a ligament is more lax, it doesn’t protect the joint as well. So in order to protect the joint, the muscles have to work harder,” Hunt said. “In that sense, it can cause the ligament to be more at risk for injury.”

In addition, women have smaller ACLs, which, when put under sudden or continual stress, often cannot handle the forces put on it during athletic involvement, so it tears.

Other injuries that occur more often in women, like IT band syndrome, also relate back to anatomy.

“The IT band is a muscle that inserts at the top of the hip and travels down in a very fibrous band to just below the knee,” Hunt said. “A lot of athletes, especially runners, have tightness in their IT band. When this band is disfunctioning and/or tight, it causes an imbalance around the pelvis and the knee and pulls the knee outward.”

“Men have it too, but women are more at risk because of the angle and shape of their pelvis,” Hunt said.

Hunt and Prather also reported on the female athlete triad, “a syndrome where female athletes are more at risk for disordered eating, menstrual function disorder and osteoporosis,” said Hunt.

The triad usually affects young women prior to menstruation or women whose periods are few and far between. “They have a hypo-estrogen state, so their estrogen levels are lower, and that can cause problems with their bone health. Recent studies have actually shown that it can cause long-term bone problems as well as cardiovascular problems,” Hunt explained.

Hunt advised athletic women to avoid calorie deficits, making sure that their intake equals their output.

“Nutritional status is very important, [especially] calcium and vitamin D,” she said, recommending 1,500 mg of calcium a day and 400 mg of vitamin D.

Vitamin D helps with the absorption of calcium, an element that, among other things, helps with bone density and muscle movement. Calcium can be found in a variety of products, like dairy foods, leafy greens, nuts and meat.

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